VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   7125
   ClientLeft      =   1860
   ClientTop       =   750
   ClientWidth     =   5100
   LinkTopic       =   "Form1"
   ScaleHeight     =   7125
   ScaleWidth      =   5100
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   375
      Left            =   3720
      TabIndex        =   0
      Top             =   6480
      Width           =   1215
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    'PROGRAM D12R4
    'Driver for routine SINFT
    EPS = 0.001
    NP = 16
    NPP2 = NP + 2
    Width1 = 30#
    PI = 3.14159
    Dim DATA(16), SIZE1(16)
    N = NP / 2
    Print
    Print Tab(5); "Period of sinusoid in channels (2-";
    Print Format$(NP, "##"); "; or 0 to stop)"
    PER = 16
    If PER <= 0# Then Exit Sub
    For I = 1 To NP
        DATA(I) = Sin(2# * PI * (I - 1) / PER)
    Next I
    Call SINFT(DATA(), NP)
    BIG = -10000000000#
    SMALL = 10000000000#
    For I = 1 To NP
        If DATA(I) < SMALL Then SMALL = DATA(I)
        If DATA(I) > BIG Then BIG = DATA(I)
    Next I
    SCAL1 = Width1 / (BIG - SMALL)
    For I = 1 To NP
        NLIM = Int(SCAL1 * (DATA(I) - SMALL) + EPS)
        Print Tab(5); Format$(I, "##");
        For J = 1 To NLIM + 1
            Print "*";
        Next J
    Next I
    Call SINFT(DATA(), NP)
    BIG = -10000000000#
    SMALL = 10000000000#
    For I = 1 To NP
        If DATA(I) < SMALL Then SMALL = DATA(I)
        If DATA(I) > BIG Then BIG = DATA(I)
    Next I
    SCAL1 = Width1 / (BIG - SMALL)
    For I = 1 To NP
        NLIM = Int(SCAL1 * (DATA(I) - SMALL) + EPS)
        Print Tab(5); Format$(I, "##");
        For J = 1 To NLIM + 1
            Print "*";
        Next J
    Next I
End Sub
Sub SINFT(Y(), N)
    THETA = 3.14159265358979 / N
    WR = 1#
    WI = 0#
    WPR = -2# * Sin(0.5 * THETA) ^ 2
    WPI = Sin(THETA)
    Y(1) = 0#
    M = N / 2
    For J = 1 To M
        WTEMP = WR
        WR = WR * WPR - WI * WPI + WR
        WI = WI * WPR + WTEMP * WPI + WI
        Y1 = WI * (Y(J + 1) + Y(N - J + 1))
        Y2 = 0.5 * (Y(J + 1) - Y(N - J + 1))
        Y(J + 1) = Y1 + Y2
        Y(N - J + 1) = Y1 - Y2
    Next J
    Call REALFT(Y(), M, 1)
    Sum = 0#
    Y(1) = 0.5 * Y(1)
    Y(2) = 0#
    For J = 1 To N - 1 Step 2
        Sum = Sum + Y(J)
        Y(J) = Y(J + 1)
        Y(J + 1) = Sum
    Next J
End Sub
Sub REALFT(DATA(), N, ISIGN)
      THETA = 6.28318530717959 / 2# / N
      C1 = 0.5
      If ISIGN = 1 Then
          C2 = -0.5
          Call FOUR1(DATA(), N, 1)
      Else
          C2 = 0.5
          THETA = -THETA
      End If
      WPR = -2# * Sin(0.5 * THETA) ^ 2
      WPI = Sin(THETA)
      WR = 1# + WPR
      WI = WPI
      N2P3 = 2 * N + 3
      For I = 2 To N / 2 + 1
          I1 = 2 * I - 1
          I2 = I1 + 1
          I3 = N2P3 - I2
          I4 = I3 + 1
          WRS = CSng(WR)
          WIS = CSng(WI)
          H1R = C1 * (DATA(I1) + DATA(I3))
          H1I = C1 * (DATA(I2) - DATA(I4))
          H2R = -C2 * (DATA(I2) + DATA(I4))
          H2I = C2 * (DATA(I1) - DATA(I3))
          DATA(I1) = H1R + WRS * H2R - WIS * H2I
          DATA(I2) = H1I + WRS * H2I + WIS * H2R
          DATA(I3) = H1R - WRS * H2R + WIS * H2I
          DATA(I4) = -H1I + WRS * H2I + WIS * H2R
          WTEMP = WR
          WR = WR * WPR - WI * WRI + WR
          WI = WI * WPR + WTEMP * WPI + WI
      Next I
      If ISIGN = 1 Then
          H1R = DATA(1)
          DATA(1) = H1R + DATA(2)
          DATA(2) = H1R - DATA(2)
      Else
          H1R = DATA(1)
          DATA(1) = C1 * (H1R + DATA(2))
          DATA(2) = C1 * (H1R - DATA(2))
          Call FOUR1(DATA(), N, -1)
      End If
End Sub
Sub FOUR1(DATA(), NN, ISIGN)
      N = 2 * NN
      J = 1
      For I = 1 To N Step 2
          If J > I Then
              TEMPR = DATA(J)
              TEMPI = DATA(J + 1)
              DATA(J) = DATA(I)
              DATA(J + 1) = DATA(I + 1)
              DATA(I) = TEMPR
              DATA(I + 1) = TEMPI
          End If
          M = N / 2
          While M >= 2 And J > M
              J = J - M
              M = M / 2
          Wend
          J = J + M
      Next I
      MMAX = 2
      While N > MMAX
          ISTEP = 2 * MMAX
          THETA = 6.28318530717959 / (ISIGN * MMAX)
          WPR = -2# * Sin(0.5 * THETA) ^ 2
          WPI = Sin(THETA)
          WR = 1#
          WI = 0#
          For M = 1 To MMAX Step 2
              For I = M To N Step ISTEP
                  J = I + MMAX
                  TEMPR = CSng(WR) * DATA(J) - CSng(WI) * DATA(J + 1)
                  TEMPI = CSng(WR) * DATA(J + 1) + CSng(WI) * DATA(J)
                  DATA(J) = DATA(I) - TEMPR
                  DATA(J + 1) = DATA(I + 1) - TEMPI
                  DATA(I) = DATA(I) + TEMPR
                  DATA(I + 1) = DATA(I + 1) + TEMPI
              Next I
              WTEMP = WR
              WR = WR * WPR - WI * WPI + WR
              WI = WI * WPR + WTEMP * WPI + WI
          Next M
          MMAX = ISTEP
      Wend
End Sub